An organic electrophotographic photosensitive member (hereinafter, sometimes referred to as “electrophotographic photosensitive member”) containing an organic photoconductive substance has been vigorously developed as an electrophotographic photosensitive member to be mounted on an electrophotographic apparatus. In addition, at present, the organic electrophotographic photosensitive member has been a mainstream electrophotographic photosensitive member to be used in the process cartridge of an electrophotographic apparatus or in the electrophotographic apparatus, and has been put into large-scale production. Of such organic electrophotographic photosensitive members, a laminated electrophotographic photosensitive member has been frequently used. The laminated electrophotographic photosensitive member improves its features by separating functions needed for an electrophotographic photosensitive member into its respective layers.
A method involving dissolving a functional material in an organic solvent to produce an application solution and applying the solution onto a support has been generally employed as a method of producing the laminated electrophotographic photosensitive member. Of the respective layers of the laminated electrophotographic photosensitive member, a charge transporting layer is often required to have durability. Accordingly, the thickness of a coat of the application liquid for the charge transporting layer is larger than that of any other layer and hence the usage of the application liquid for the charge transporting layer is also large. As a result, the layer uses a large amount of the organic solvent. To curtail the usage of the organic solvent at the time of the production of the electrophotographic photosensitive member, the amount of the organic solvent to be used in the application liquid for the charge transporting layer is desirably curtailed. However, the production of the application liquid for the charge transporting layer requires the use of a halogen-based solvent or an aromatic organic solvent because a charge transporting substance and a resin each have high solubility in any such solvent. Accordingly, it has been difficult to curtail the usage of the organic solvent.
Patent Literature 1 reports an effort to curtail the amount of an organic solvent in a paint for forming a charge transporting layer for the purposes of reducing a volatile substance and curtailing carbon dioxide. This literature discloses that an emulsion for the charge transporting layer is produced by forming oil droplets of an organic solution, which is prepared by dissolving a substance to be incorporated into the charge transporting layer in an organic solvent, in water.